The tab for the latest copper caper has not been calculated, but these thefts cost the district more than $300,000 last year, said Robert Laughton, LAUSD deputy director of maintenance and operations.

“This has been a big problem for a while. I can’t remember not experiencing the theft of copper at some level,” he said. District officials were not able to provide a comparison with 2012 losses.

LAUSD police did take down two copper-theft rings last year, Laughton noted, though he declined to provide details of those operations.

Norma Marpel, the plant manager for Encino Charter at 16941 Addison St., whose first job each day is to confirm the drinking fountains and faucets are working, discovered the problem as soon as she arrived on campus, said Principal Marcia Koff.

And it looked like a professional job, she noted. “They cut a hole in the security fence. It’s a big chain-link fence, and the hole was big enough for a couple of people to go through,” said Koff of the damage.

The school faces south along Addison, and the water equipment is encased in a cage behind a brick wall not far from where the fence was breached, she added. There is a park right across the street, but nobody noticed anything amiss.

“I had teachers working periodically over the weekend, and no one saw it. On Sunday afternoon I had a couple of teachers working in classrooms, but they wouldn’t necessarily look at where the water equipment is,” Koff said.

The thieves first shut off the water and made off with copper pipe, valves and some brass pressure regulators. Laughton said others have been known to take just the copper and brass fittings and leave pipe. The material is said to fetch about $3 a pound.

“It’s done under the cover of darkness,” he said. “The last ring we arrested (consisted) of two guys who were experienced plumbers. They took everything apart, and there was not much damage to the rest of the equipment,” he said. “The best preventive (measure) is an observant neighborhood.

In Encino, there was a quick response by district plumbers, and the school’s water was again flowing by 9 a.m.

“They did a great job,” Koff said. “The plumbers tell me they’ve been to other schools with the same problem.”

Schools are not the only facilities at risk, said Detective Randy Elzinga of the LAPD’s Mission Division. There has been an uptick on the theft of copper and brass from residential and commercial properties this year as well.

“They are taking it and selling it at scrap yards,” he said. “You can’t really trace it because there are no marks indicating where it came from.”